The fact that we're observing some volatility doesn't mean it's different in principle. I don't see any difference in incentives. Only difference is initial audience - web was being grown by tech people, and the only way to participate was to host a web server. Nostr is growing with not tech but freedom-loving people for the most parrt, who for now have some free relays serving them. 

Many tech people do have their own relays here, which aren't good for public use, and they shouldn't be. That's why we have outbox model, so that personal relays could participate. The bigger nostr gets, the more valuable being on nostr becomes, the more relays there will be, run by people with profit motives, for themselves and their following.